1. Field of the Invention
The present invention relates to an image recording apparatus which records an image upon a recording medium.
2. Description of the Related Art
Generally, an image recording apparatus such as an ink jet printer has a paper feeding unit for feeding a recording medium, a conveyance unit for conveying the recording medium from the paper feeding unit, and an image recording unit for recording an image conveyed by the conveyance unit.
The paper feeding unit houses recording media such as papers for use in image recording, OHP papers, or the like. Further, the paper feeding unit has conveying driving means such as a pickup roller in order to pick up the housed recording media and transmit a recording medium to the conveyance unit. The conveying driving means comes in contact with a recording medium, applies self driving force to the recording medium, and conveys the recording medium in a predetermined direction. The image recording unit records an image by ejecting ink with respect to the recording medium in the course of conveyance by the conveyance unit.
In this way, the conveying driving means of the paper feeding unit and the conveyance unit come in contact with a recording medium at the time of conveying the recording medium. Therefore, the recording medium generates particulate dust such as paper particles due to friction with the conveying driving means, an impact at the time of contacting, or the like. The generated particulate dust floats in the atmosphere, and drift about inside the image recording apparatus. Note that the recording medium is generally cut into a predetermined size. This cutting unit easily generates particulate dust such as paper particles. Accordingly, it is difficult to prevent particulate dust from being generated due to the friction or impact from cut regions.
Further, the recording medium is housed and stored in the paper feeding unit. Particulate dust such as dust in the atmosphere or the like is adhered to the recording media in storage. The adhered particulate dust drifts about inside the image recording apparatus by the friction or impact.
When the particulate dust made to float in this way move to the periphery of the image recording unit, there is the possibility that the particulate dust may be adhered to the image recording unit, which may have a harmful influence on a characteristic of jetting ink of the image recording unit. For example, in the case of an ink jet system image recording apparatus, the image recording unit has a nozzle which jets out ink.
In this ink jet system image recording apparatus, when the aforementioned particulate dust moves to the periphery of the image recording unit, there is the possibility that the moved particulate dust may adhere to the nozzle, or may intrude into the nozzle. When the particulate dust adheres to or intrude into the nozzle, there is the possibility that ink cannot be ejected from the nozzle, or a change in the orbit of the ejected ink (ejection curve) may be brought about.
Then, an image recording apparatus having a configuration in which particulate dust intruding into the image recording apparatus are reduced has been considered.
A conventional image recording apparatus having such a configuration is shown, for example in Jpn. Pat. Appln. KOKAI Publication No. 2003-220695 (Patent Document 1). FIG. 17 is a diagram showing the image recording apparatus in the publication.
The image recording apparatus has a recording head housing 102 in which a plurality of recording heads 104 are disposed, and a conveyance mechanism housing 101 in which a recording medium conveyance mechanism unit 105 at which a paper feeding unit is disposed is disposed. A recording medium 103 is a serial roll paper. The recording medium conveyance mechanism unit 105 is composed of conveyance rollers 106a and 107a, pressing rollers 106b and 107b, and rollers 108 and 109.
The recording head housing 102 and the conveyance mechanism housing 101 are connected through openings 112a and 112b, and are configured such that air can be circulated via these openings 112a and 112b each other. The recording heads 104 are an image recording unit which records an image by ejecting ink with respect to the recording medium 103.
Fans 114 and 115 are provided in the recording head housing 102, and air is made to flow into the recording head housing 102 from the exterior by the fans 114 and 115. The air is guided by a wind direction guide 141, and is made to flow into the conveyance mechanism housing 101 via the openings 112a and 112b. According to the above-described configuration, the image recording apparatus of Patent Document 1 brings about an airflow flowing from the side of the recording heads 104 to the side of the paper feeding unit (in the up and down direction in FIG. 17) in order to prevent paper particles or particulate dust from adhering to the ink jet heads.
In the image recording apparatus disclosed in Jpn. Pat. Appln. KOKAI Publication No. 2003-220695 described above, the recording head housing 102 and the conveyance mechanism housing 101 including a paper feeding region at which paper feeding is carried out are connected so as to eject particulate dust from the recording head housing 102 including an image recording region at which image recording is carried out. In addition thereto, the wind direction guide 141 is configured in order to prevent the air which has been blown from the fans 114 and 115 from directly blowing against the recording heads 104, and an interval with the recording medium 103 has been not considered. Accordingly, an attempt that the image recording region and the paper feeding region are spatially separated is not made.
Moreover, with respect to the recording head housing 102, an attempt that the image recording region and the other regions are spatially separated is not made. Therefore, with respect to the image recording region at which the recording heads 104 are provided, a preventing measure for that paper particles intrude from the direction crossing the aforementioned airflow (the cross direction in FIG. 17) has been not considered, and there has been the possibility that particulate dust from this direction may intrude depending on the convection of air.